Computational insights into glycerol hydrogenolysis over PtnCu4-n (n: 1–3) nanocluster embedded on oxygenated graphene: A DFT investigation

Excessive biofuel production research resulted in overabundance of glycerol and consequently making it less valuable chemicals compared to the old times. Fortunately, glycerol can be utilized as building block for many important and value-added chemicals such as propanediols and propanol. In this work, we investigated catalytic glycerol hydrogenolysis over the surface of various bimetallic PtnCu4-n anchored on oxygenated graphene through density functional theory (DFT) calculations. Systematical study on the C-OH cleavage and C-H bond formation of glycerol was carried out to determine the transformation process into lesser alcohol products such as propanediols and propanol. It is found that different number of Pt and Cu in the nanocluster regulates the product selectivity. The Pt3Cu1 model is selective towards 1,2-propanediol (1,2-PDO) and 1-propanol (1-PrOH) production with the energy barrier of 0.91 and 1.32 eV, respectively. Meanwhile, Pt1Cu3 catalyst has more potential for 1,3-propanediol (1,3-PDO) production with the energy barrier of 1.01 eV. The C-OH cleavage step was found out to be the rate-determining step on both pathways. Difference in product selectivity arose from the structural integrity of PtnCu4-n nanocluster maintained during the hydrogenolysis process. This research may become guidance for glycerol valorization using graphene-supported bimetallic catalyst on the experimental level